Drawbench with a drawing chain rotating continuously in the same direction



I April 2, 1957 A. KREIDLER v DRAWBENCH WITH A DRAWING CHAIN ROTATING CONTINUOUSLY IN THE SAME] DIRECTION Filed June 3, 1952 INVE/WM? a W DRAWBENCH WITH A DRAWING CHAIN ROTAT- ENG CUNTINUOUSLY IN THE SAME DIRECT [N Alfred Kreidler, Stuttgart, Germany Application June 3, 1952, Serial No. 291,375 laims priority, application Germany June 6, 1951 2 Claims. (Cl. 205-3) The present invention concerns drawbenches for draw ing work such as metallic bars or tubes through dies.

Drawbenches are frequently constructed in such a way that at the draw-in position of the drawbenches after gripping the pointed end of the work inserted through the die into the gripper disposed at the draw end, the hook of the carriage is coupled to the drawing chain continuously rotating in the same direction and is uncoupled upon the completion of the drawing operation, whereupon the carriage-either by cable traction or rolling back on obliquely inclined drawbench bed-returns to the draw-in position. I

In order to avoid the loss of time occasioned by the return movement of the carriage, drawbenches have al ready been equipped with two carriages, whilst at any given moment the carriage coupled to the chain moves in the direction of drawing, and whilst the other carriage which is uncoupled from the chain returns on a side line in the manner described above to the initial position. In addition to the coupling and uncoupling of the carriages, it was also necessary to shunt them on to the side-line, and this involved a rather complicated construction. In this case also the carriages had 'at first to be accelerated and then to be slowed down in order to return to their direction of motion which required corresponding expenditure of energy.

In the case of other drawbenches the carriages were coupled continuously with the draw chain, but with these the chain was reversed in order to return the carriage to the initial position. Benches of this kind have already been constructed with two carriages running in opposite directions on separate tracks. In this case the coupling and uncoupling can certainly be omitted; instead, however, the whole drive and of course also the carriages themselves had to be reversed which again led to complications and a large expenditure of energy. In all cases, however, such drawbenches constructed as double benches had to be of correspondingly large proportions, which caused a not inconsiderable demand for material and space.

It is, therefore, one object of the present invention, to provide, in contrast to the known methods, an astonishingly simple method which allows the above described disadvantages to be avoided. It is another object of the present invention, to provide a method according to which a drawbench with a drawing chain rorating continuously in the same direction is equipped with two or more carriages coupled continuously with the drawing chains, each carriage having the usual tongs and running on a closed track.

It is yet another object of the present invention to provide a drawbench in which each uncoupling and reversing is omitted and the bench does not need to be constructed more strongly than a simple drawbench.

It is a further object of the present invention to provide a drawbench in which in order to manage with a short end to be pointed on the drawbench and in order to keep the bench as short as possible, it is preferable nited States Patent ice if the tongs swing into the direction of drawing an out flanged arrangement on the carriage, for example, on a shallow curved path directly arriving before the die.

With these and other objects in view, which will become apparent in the following detailed description, the present invention will be clearly understood in connection with the accompanying drawing, in which:

The single figure illustrates diagrammatically an embodiment with two carriages, in its essential parts as a side elevation (partly in section).

Referring now to the drawing, the drawing chain 3 passes over the drive chain wheel 1 which can be rotated by an electric motor, and over two guide wheels 2. Two carriages 4 are each secured by means of two eyes to the draw chain 3.

Each carriage 4 is guided by a roller 6 which during the drawing operation rolls oit on the upper surface of the drawbench frame 8 forming a track 7 and during its return stroke rolls on a lower return track 9, which comprises a substantially straight portion and an upwardly directed curved portion B, the latter forming with the curved end face 8 of the drawbench frame 8 a double track for the roller, thereby providing a safe guide for the carriages 4 to the top track 7 of the drawbench frame.

A die 10 is secured to a die holder 11.

On the draw-in side of the drawbench the drawing chain 3 guides the carriage 4 by way of its positions shown in dotted lines from the return track into the draw line. Whilst the eyes 5 of the carriage describe a regular are A over the whole operation, the tongs 12 are disposed on a rearwardly projecting or offset portion of the carriage and thus pass through the shallow, substantially arcuate track B and track 8' which is substantially parallel to track B close to the die 10, and then swing in a short curve, with a short forward motion and a kind of sharp bend into the horizontal draw line. The tongs 12 execute the motion described with their open jaws on both sides of the sharpened end of the work 13 projecting out of the die; the work is then partially engaged by the jaws and if these jaws are now closed by the operator by reversing the lever 14, they seize the bar and begin the drawing operation.

As soon as the bar subjected to the drawing operation is drawn through the die the draw resistance holding the jaws of the tongs closed ceases and the jaws open by spring operation or the like, whereupon carriage and work separate again.

The work is now taken off by the drawbench.

The carriage is swung at the end of the drawbench, around the chain wheel 1 downwards onto the return track 9 and there returns to the draw-in side of the drawbench, whereupon the above described operation is repeated. By the above described manner in which the tongs approach to the die in a shallow curve and in which the tongs subsequently swing in a short curve into the line of drawing, it is possible to manage with a short pointing of the bar or the tube in contrast to the conditions in the case of a regularly circular track which requires spaced interval of the die holder from the swing-in point of the tongs into the line of drawing and hence a longer pointing of the work.

The use of at least two carriages avoids wasted time, since while one carriage is being used for the drawing operation, the other executes its return stroke.

While I have disclosed one embodiment of the present invention, it is to be understood that this embodiment is given by example only and not in a limiting sense, the scope of the present invention being determined by the objects and the claims.

I claim:

* '1. A' drawbench comprising in combination a die, an endless drawing chain adapted to move continuously in the same direction, at l easttwo carriages permanently secured to and spaced apart on the'said endless drawing chain and moving continuously together with said endless drawing chain, each of said carriages having guide rollers, tongs on each of the said carriages, a first track cooperating with said guide rollers for the forward movement of the said carriages during the drawing operation and consisting of a curved end portion and a substantially straight portion, a second track cooperating with said guide rollers for the-return movement of the said carriages upon termination of the drawing operation and consisting of a substantially straight portion and a curved end portion,-both said curved end portions being equally spaced from each other a-distance substantially equal to the diameter of said guide rollers, said curved end portions being close to said die and providing an uninterrupted return movement of the said carriages to the said first track close to the said die.

2. In a drawbench, a die, an endless drawing chain adapted to move continuously in the same direction, a carriage permanently secured to and partly supported by the said endless drawing chain and moving continuously together with the said endless drawing chain and said carriage having guide rollers, tongs on the said carriage, thesaid endless drawing chain passing round an arcuate path immediately prior to a substantially straight run for the drawing operation, a first track cooperating with said guide rollers for the forward movement of the said carriage during the drawing operation and consisting of a curvedend portion and a substantially straight portion, a second track cooperating with said guide rollers for the return movement of the said carriage upon termination of the drawing operation and consisting of a substantially straight portion and a curved end portion, both said curved end portions being equally spaced from each other a distance equal to the diameter of said guide rollers, said curved end portions being close to saiddie and providing.antuninterrupted return movement of the said carriage tothe said first track close to the said die, the said carriage being partly supported by the said corresponding tracks during the movement of the said endless drawing chain, and the diameter of the curved portion of the'said second track being larger than that of the arcuate path of the said chain.

ReferencesyCitedin the file of this patent UNITED STATES PATENTS 311,213 Van Derzee Jan. 17, 1885 1,124,757 Lloyd Jan. 12, 1915 1,281,668 Saunders Oct. 15, 1918 1,742,074 Hires Dec. 31, 1929 1,911,157 Leech May 23, 1933 2,320,739 Knudsenet al. June 1, 1943 FOREIGN PATENTS 477,983 Canada Oct. 23, 1951 774,681 France Dec. 11, 1934 

